Siemens SENTRON 5SY4140-7KK11 — C-curve MCB for panel protection
Its C-curve tripping characteristic means it holds through moderate inrush — typical for motor-starter and contactor coils, small transformers, and capacitor banks — and trips on sustained overloads at 5–10× rated current. The interrupting capacity is 10 kA per EN 60898-1 and 15 kA per IEC 60947-2, giving headroom for most 400 VAC industrial supply points with fault currents under that threshold. At 18 mm wide, it occupies one modular unit on DIN rail — standard for a single-pole MCB — and mounts in any position.
Rated per DIN EN 60898-1 for residential and similar installations, and per IEC 60947-2 for industrial application. The overvoltage category is III, degree of pollution 3, and energy limitation class 3 — meaning it limits let-through energy to a defined level for downstream equipment protection. The design is halogen-free and silicon-free, suitable for environments sensitive to corrosive off-gassing (railway, marine, clean manufacturing). The product designation explicitly notes suitability for railway applications.
Voltage ratings and application range
Rated operating voltage is 400 VAC with a maximum of 440 VAC in single-phase or multi-phase operation. For DC circuits, the rated value is 60 V with a maximum of 72 V. Frequency range is 50/60 Hz. The C-curve and 1-pole design make it a direct fit for single-phase final circuits in distribution boards, motor-control centers, and machine-tool panels where the upstream fault level stays within 10 kA (EN) or 15 kA (IEC).